How did private, nude photos of Jennifer Lawrence and other celebrities get leaked all over the Internet Sunday?

A combination of a common Internet scam, weak passwords and a since-fixed vulnerability in Apple's photo backup service could be to blame.

Hackers usually send fake emails, posing as their bank, Facebook or an email provider. Those so-called phishing scams make people think they're coming from a trusted source leading them to enter their user names and passwords onto a fake website owned by hackers.

It's also possible that the hacked celebrities had easy-to-guess passwords. Typically, online services only let users guess passwords a handful of times before blocking access. But until this week, Apple's iCloud backup service allowed people to guess passwords over and over - it would never lock people out.

"We take user privacy very seriously and are actively investigating this report," said Natalie Kerris, an Apple spokeswoman.